pass-lang/src/asm.c

/// This file handles the contextual generation of machine code.
/// It abstracts over quirks like the limitations of addressing modes,
/// provides higher-level functionality, and can perform peephole optimization.

#include "asm.h"
#include "format.h"
#include "x86encode.h"

#include <stdlib.h>
#include <string.h>

void inst_jump(symbol sym) {
    int32_t disp = symbol_offset(sym, X86_JMP_DISP8_SIZE);
    if (disp >= INT8_MIN && disp <= INT8_MAX) {
        x86_inst_jmp_disp8(disp);
    } else {
        x86_inst_jmp_disp32_op();
        relocate_pc32(sym);
    }
    // TODO: support 64-bit jumps?
}

void inst_jump_if_zero(symbol sym, reg reg) {
    x86_inst_test_r64_r64(reg, reg);
    int32_t disp = symbol_offset(sym, X86_JZ_DISP8_SIZE);
    if (disp >= INT8_MIN && disp <= INT8_MAX) {
        x86_inst_jz_disp8(disp);
    } else {
        x86_inst_jz_disp32_op();
        relocate_pc32(sym);
    }
}

void inst_jump_if_not_zero(symbol sym, reg reg) {
    x86_inst_test_r64_r64(reg, reg);
    int32_t disp = symbol_offset(sym, X86_JNZ_DISP8_SIZE);
    if (disp >= INT8_MIN && disp <= INT8_MAX) {
        x86_inst_jnz_disp8(disp);
    } else {
        x86_inst_jnz_disp32_op();
        relocate_pc32(sym);
    }
}